5-dialkylaminomethyl-2- furanomethanol, which is represented by formula (A) below, has been known since 1947. ##STR2##
The above compound represented by formula (A) has only been used since 1976 for the synthesis of antiulcer drugs, due to the discovery of the antiulcer drug ranitidine. In most cases, the use of the compound represented by formula (A) above has been limited to the preparation of the corresponding furanomethyl thioethers.
Heretofore, among esters of the compound represented by formula (A), only those of sulfuric acid have been known. These compounds are known to be useful as antiulcer drugs.
Prior to the present invention there was no teaching or suggestion that such compounds would be effective on blood circulation, i.e., to have calcium-antagonistic and antihypertensive properties
Although 1, 4-dihydropyridine-3, 5-dicarboxylic esters containing furano rings in the ester radical are known (Chem. Abstr. 75:151587d; and Chem. Abstr. 100:85591z), esters having the substituents shown in the compound represented by (A) have not been known.